Fluid-assisted plow

ABSTRACT

A system for digging a trench in the ground is provided. The system includes a power driven land vehicle having a front end and a rear end; a plow blade connected to the rear end of the vehicle; spray nozzles connected to the plow blade and positioned to spray liquid onto the plow blade; and a tank attached to the front of the vehicle to supply liquid to the spray means.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] This invention relates to plows for digging trenches in the earth. The plow can be of the type which is mounted on a vehicle such as a tractor and it can be part of a system for installing electrical cable or other flexible tubing in the ground.

[0003] 2. Description of the Prior Art

[0004] In the past there have been a variety of approaches to digging trenches in the earth for a variety of purposes. One example is an underground cable installing apparatus such as is taught in U.S. Pat. No. 4,498,813. That patent teaches an apparatus which uses a power driven land vehicle and an elongated cable laying plow supported by and for movement with the vehicle. The lower part of the plow blade is pulled through the ground by the vehicle so that the cutting edge of the plow blade creates a trench in the earth. The vehicle carries a cable reel on the front part of the vehicle and the cable travels from the reel to the rear end of the vehicle and is deposited in the trench behind the plow. The patent also teaches a plurality of high impact fluid jets incorporated into the cutting edge of the plow blade. The fluid jets direct fluid at high pressure toward the earth in front of the blade to assist the blade in cutting therethrough.

[0005] Other types of conventional systems for underground cable installation are similar to the system taught in U.S. Pat. No. 4,498,813 but they do not use fluid with the plow; rather, the plow blade is dry. Such systems include a cable reel mounted to a reel support structure located at the forward end of the trenching vehicle. The vehicle includes a cable transport system to convey cable from the reel to the rear of the vehicle so that the cable is placed in the trench behind the plow blade as the vehicle pulls the plow blade forward to form the trench.

SUMMARY OF THE INVENTION

[0006] According to one aspect of the invention, a system for digging a trench in the ground is provided, which includes a power driven land vehicle. A fluid-assisted plow blade is mounted to the rear end of the vehicle so that as the vehicle travels forward the plow blade digs a trench in the ground. A spray system is connected to the plow blade and positioned to spray water onto the plow blade and the earth, which provides lubrication and assists the blade in cutting through the earth. A tank is attached to the front of the vehicle to carry a supply of water, and a pump is provided to pump water to a hose system to feed water to the spray system. The spray system is designed so that spray nozzles and other relatively vulnerable parts of the system are located where they are protected from direct contact with the earth, and especially direct contact with the earth at the forward edge of the plow blade where they could easily be damaged by such contact.

[0007] According to another aspect of the invention a conversion system and process are provided for converting a conventional dry-type cable laying trenching plow system to a fluid-assisted system. The conversion system according to this aspect of the invention includes a water tank support structure which is designed to be easily coupled to the cable reel support assembly. The cable reel is removed from the support assembly, and the water tank support structure is attached to the support structure in place of the cable reel. A water tank is then mounted on the support structure, and a pump and hose system is connected to convey water from the tank. The existing dry-type plow blade is removed and replaced with a fluid-assisted plow blade, and the hose system is coupled to the plow blade spray system. The fluid-assisted plow blade can be of a conventional type, or the blade can be one according to the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008]FIG. 1 is an elevation view of an underground cable-laying apparatus of the prior art.

[0009]FIG. 2 is an elevation view one embodiment of the overall system of the present invention.

[0010]FIG. 3 is an isometric view of the water containment system.

[0011]FIG. 4 is an elevation view of an embodiment of the fluid-assisted plow blade.

[0012]FIG. 5 is an elevation view of part of the plow blade of FIG. 4.

[0013]FIG. 6 is a cross section of the plow blade of FIG. 5 taken along line 6-6.

[0014]FIG. 7 is elevation view of an alternative embodiment of a fluid-assisted plow blade.

[0015]FIG. 8 shows a portion of the plow blade of FIG. 7.

[0016]FIG. 9 shows a cross section of the blade shown in FIG. 8, taken along line 9-9.

[0017]FIG. 10 shows the portion of the blade in FIG. 7 as viewed from line 10-10.

[0018]FIG. 11 shows a cross section of the blade of FIG. 7 and illustrates how water is sprayed from the blade.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] Turning to the drawings, wherein like components are designated by like reference numbers throughout the various figures, attention is directed to FIG. 1.

[0020] In FIG. 1 there is shown an underground cable laying apparatus 10 of the prior art, which includes a power driven land vehicle 12 having a front end 14 and a rear end 16. The apparatus has a right side 20, which is visible in this figure and a left side, which is not visible in this figure, and tractor treads 26. The vehicle 12 also includes a cable reel support assembly 30 to support a cable reel 32. A cable-laying plow blade 34 is connected to the rear end 16 of the vehicle 12.

[0021] The cable reel 32 carries a supply of cable 35 to be installed in the ground 36 and an arrangement for feeding the cable from its supply to a location in a trench in the ground 36 behind the blade 34 as the vehicle travels forward, i.e. from left to right in FIG. 1.

[0022] Turning now to FIG. 2 there is shown one embodiment of the fluid-assisted plow system according to the present invention. A power driven land vehicle 12 has a support assembly 40 affixed to its front end 14. The support assembly 40 includes two arms 42, one coupled to each side of the vehicle 12 by hinges 44 and a hydraulic system 46 so that an operator can use the hydraulic system 46 to raise and lower the arms 42 about the hinges 44. A water supply system 50 is coupled to the front end of the arms 42. The water supply system 50 includes a tank 51 to contain a quantity of water and also includes a pumping system 74 which pumps water through conduit 52. The water supply system 50 is described further below and shown in FIG. 3. The conduit 52 extends from the water supply system 50 along the side of the vehicle 12 to the fluid-assisted plow 60 mounted to the rear end 16 of the vehicle by a linkage system 62.

[0023]FIG. 3 shows the water supply system 50 which includes a tank 51 to contain water or other appropriate fluid. Attached at the top of the tank is a fill hatch 70 which can be opened to permit water to be delivered into the tank 51 and a container 72 to hold secondary fluid which can be added to the water as it is delivered at a controllable rate from the tank 51 to the plow 60. The secondary fluid can be a liquid polymer, for example, to enhance the operation of the plow blade. A pump system 74 is connected to the tank 51 to pump water from the tank 51 to conduit 52.

[0024] The tank 51 is supported and contained by a carriage structure which includes a plurality of horizontal members 80 beneath the tank 51 and forward and rear vertical supports 82 and 84, respectively. Four angled supports 86 are connected to the sides of horizontal members at their lower ends and to a horizontal axle member 88 at their upper ends. The horizontal axle member 88 has two linkage structures 90, one at each end, which can be connected to the arms 42 of the power driven land vehicle 12.

[0025] Turning now to FIG. 4, there is shown one embodiment of a fluid-assisted plow 100 in accordance with the present invention. The fluid-assisted plow 100 includes a shank 102 having an upper section 104 and a lower section 106. Three holes 110 are formed through the upper section 104 to accept pins, not shown, for attachment to the vehicle 12. The forward part of the plow 100 is substantially triangular in cross section to provide a knife-like cutting edge, and a plurality of grooves 112 are formed in both forward surfaces of the cutting edge as shown in more detail in FIGS. 5 and 6. Two lugs 114 and 116 are affixed to the rear edge of the shank 102 to cooperate with four lugs 120 formed on the forward edge of a cable chute assembly 126. A pin, not shown, is inserted through each set of cooperating lugs in order to form two hinges so that the cable chute assembly is articulated relative to the shank 102. The cable chute assembly 126 includes a channel having a substantially rectangular cross section to accept conduit which is being laid in the channel formed by the plow 100.

[0026] A pipe 130 is coupled to the upper section 104 of the shank 102. The upper end of the pipe 130 is connected to the conduit 52 to carry water from the water supply system 50. The lower part of the pipe 130 is connected to a channel, not shown, which is formed in the shank 102.

[0027] Turning to FIG. 5, there is shown a section of the forward portion of the lower section 106 of the shank 102. The forward section shown in FIG. 5 is knife-like and serrated with a plurality of grooves 112. A plurality of spray systems 132 are formed in the shank 102 rearward of the grooves 112. A substantially vertical channel 134 is formed through the shank 102 and connected to the pipe 130 to permit water to flow from the water supply system 52 to spray systems 132.

[0028]FIG. 6 shows a sectional view of the portion of the plow shown in FIG. 5. The forward most part 140 of the plow shown in FIG. 6 is substantially triangular in cross-section and two channels 142 are semi-circular and are formed in the left and right faces of the forward most part 140. The channel 134 is formed in the forward most part 140. Rearward of the forward most part 140 is a spray housing section 144, and rearward of section 144 is distal section 146. A plurality of cylindrical holes 150 are formed in the spray housing section 144, and rearward of the cylindrical holes are mounted a plurality of spray nozzles 152. Two cylindrical holes 150 and two spray nozzles 152 are included in each spray system 132. Each spray system 132 also includes two semi-circular channels 156 formed in the distal section 146, one in the left face and one in the right face.

[0029] Thus it can be seen that in operation water is supplied under pressure to the channel 134. From the channel 134 the water flows through holes 150 and then through spray nozzles 152. From the nozzles 152 the water forms sprays shown by dotted lines 160, and the sprays 160 partly impinge on the channels 156 to travel generally downwardly in FIG. 6, which is rearwardly when the plow is in normal operating position. Accordingly, the water lubricates the distal section 146 of the plow blade and those other parts of the blade rearward of the spray nozzles 152, and the water also lubricates the earth surrounding the blade.

[0030] It should be understood that the spray systems 132 are designed to be protected from substantial contact with the earth to reduce wear and tear and possible damage. As the plow cuts through the earth, the forward most part 140 of the plow blade contacts the earth and breaks it apart and separates it with the knife-like forward edge of the blade. The spray systems 132 are located behind the forward most part 140 of the plow blade and substantially enclosed within the blade so that the spray systems 132 and particularly the spray nozzles 152 do not have substantial contact with the earth and are thus protected. Also, the spray housing 144 is wider than the distal section 146 to provide further protection for the semi-circular channels 156 from contact with the earth. Another significant feature of the present embodiment is that the spray systems 132 are oriented to spray water in a direction which is not directly opposite to the direction of travel of the plow. Because of this the spray nozzles 152 are not oriented with their openings directly opposed to the earth in front of the blade and thus as the blade travels through the earth, earth is not forced into the openings of the spray-nozzles and possible clogging of the nozzles and damage to the nozzles is reduced.

[0031] Turning now to FIGS. 7-11 there is shown an alternative embodiment of the fluid-assisted plow blade. In this embodiment a shank 162 has three holes 110 in its upper section to be affixed to the vehicle 12. A plow blade assembly 164 is affixed to the front side of the shank 162 and spray means are coupled to the blade assembly. The blade assembly 164 includes a forward part 166 which is generally triangular in cross section and has two faces 167 and 169 which meet at a vertex 168. A plurality of semi-cylindrical channels 170 are formed on each face 167 and 169, and the vertex of the forward part includes semi-circular serrations 172. The blade assembly 164 also includes a rearward part 174 which has a cylindrical water conduit 176 formed to extend along its length and a plurality of semi-cylindrical spray openings 178 which are formed in the face of the rearward part. The water conduit 176 is coupled in fluid flow communication with pipe 130, and the spray openings are connected to the water conduit 176 by a plurality of spray conduits 180. Accordingly, when water is pumped into the pipe 130 the pressurized water flows out the spray openings 178.

[0032] The plow blade assembly 164 is mounted to the front of the shank 162 as shown in FIG. 11. The width of the blade assembly 164 is somewhat larger than the width of the shank 162 and thus it can be understood that when pressurized water leaves the spray openings 178 the water is dispersed against the forward face of the shank 162 and directed primarily outwardly from the shank 162 as shown by arrows. As the plow moves forward through the earth water directed onto the earth and is carried rearward onto the shank to provide lubrication between the shank and the earth.

[0033] It should be understood that the water spray systems of the embodiment shown in FIGS. 7-11 are designed to have reduced susceptibility to wear and tear and possible clogging. First of all, the spray systems do not include conventional nozzles to disperse the water, and therefore, of course, there is no nozzle with a small bore to become clogged with earth. Moreover, as the plow cuts through the earth, the vertex 168 of the plow blade contacts the earth and breaks it apart and separates it with the knife-like forward edge of the blade. The spray openings 178 are located behind the forward part 166 of the plow blade and substantially enclosed within the blade so that the spray openings 178 and the spray conduits 180 do not have substantial contact with the earth and are thus protected. Also, the forward part 166 is wider than the shank 162 to provide further protection for the spray system from contact with the earth.

[0034] Another significant feature of the present embodiment is that the spray system are oriented to spray water in a direction which is not directly opposite to the direction of travel of the plow. Because of this the spray openings 178 are not oriented directly opposed to the earth in front of the blade and thus as the blade travels through the earth, earth is not forced into the openings 178, and possible clogging of the openings and damage to the openings and the spray system is reduced.

[0035] Turning again to FIGS. 1 and 2 it can be understood how a system for laying cable using a conventional dry-type plow is converted to a fluid-assisted plow system according to an embodiment of the present invention. Initially the dry-type plow system is substantially as shown in FIG. 1. Then the cable reel 32 is removed from the reel support assembly 30 and replaced with the water supply system 50 by attaching the linkage structures 90 to the two arms 42. Then the conventional dry-type plow blade is removed from the rear of the vehicle 16 and replaced with a fluid—assisted plow blade which can be of a known construction or according to an embodiment of the present invention disclosed herein. Then conduit 52 is connected between the pump 74 and the fluid assisted plow, e.g. plow 60. The system is then in the configuration shown in FIG. 2. 

1. A system for digging a trench in the ground, comprising: a) a power driven land vehicle having a front end and a rear end; b) a plow blade connected to the rear end of the vehicle; c) spray means connected to the plow blade and positioned to spray liquid onto the plow blade; and, d) a tank attached to the front of the vehicle to supply liquid to the spray means.
 2. A conversion system for converting the cable support assembly of a trenching plow to a liquid-supply system, the conversion system comprising: a) vertical support structure to be coupled to the cable support assembly; b) horizontal support structure to be coupled to the vertical support structure; c) a tank to be mounted on the horizontal support structure; and, d) means to convey fluid from the tank to said spray means.
 3. A process for converting a cable-laying trenching plow having a vehicle and a plow blade to a fluid-assisted plow system, the process comprising: a) removing the cable reel support structure from the cable-laying trenching plow; b) removing the plow blade; c) affixing a fluid-supply system to the cable reel support structure; d) affixing a plow blade having spray means to the end of the vehicle; and, e) connecting the fluid-supply system in fluid-flow communication with the spray means of said plow blade.
 4. A process according to claim 3 wherein said fluid supply system comprises a linkage structure and said cable reel structure comprises arms, and the process of affixing the fluid-supply system to the cable reel support structure comprises affixing the linkage structure to said arms.
 5. A fluid-assisted plow blade comprising: a) A plow blade b) Means to spray fluid onto the plow blade
 6. A plow blade according to claim 5 wherein said means to spray fluid onto the plow blade includes a plurality of nozzles.
 7. A plow blade according to claim 5 wherein said means to spray fluid onto the plow blade includes a plurality of nozzles oriented to spray fluid onto at least one of the faces of the plow blade.
 8. A plow blade according to claim 5 wherein said means to spray fluid onto the plow blade includes means to spray fluid in a direction substantially perpendicular to the direction of travel of the plow blade.
 9. A plow blade according to claim 5 wherein said means to spray fluid onto the plow blade includes a plurality of nozzles.
 10. A fluid-assisted plow blade comprising: a) A plow blade; and b) a spray system coupled to said plow blade and located so that as the plow blade travels through the earth the plow blade protects the spray system from substantial contact with the earth.
 11. A fluid-assisted plow blade comprising: a) A plow blade having a forward edge; and b) a spray system coupled to said plow blade rearward of said forward edge so that as the plow blade travels through the earth the plow blade protects the spray system from substantial contact with the earth.
 12. A plow blade according to claim 11 wherein said spray system comprises at least one spray nozzle which is directed to spray fluid in a direction other than the direction of travel of the plow blade. 